bootstd: sandbox: Add a hostfs bootdev

It is helpful to be able to try out bootstd on sandbox, using host files.
This is easier than using a block device, which must have a filesystem,
partition table, etc.

Add a new driver which provides this feature. For now it is not used in
tests, but it is likely to be useful.

Add notes in the devicetree also, but don't disturb the tests.

Signed-off-by: Simon Glass <sjg@chromium.org>

6 files changed, 70 insertions, 0 deletions

diff --git a/arch/sandbox/dts/sandbox.dts b/arch/sandbox/dts/sandbox.dts
index 127f168f022..18fde1c8c6f 100644
--- a/arch/sandbox/dts/sandbox.dts
+++ b/arch/sandbox/dts/sandbox.dts
@@ -66,6 +66,10 @@
 		fake-host-hwaddr = [00 00 66 44 22 00];
 	};
 
+	host-fs {
+		compatible = "sandbox,bootdev-host";
+	};
+
 	i2c_0: i2c@0 {
 		#address-cells = <1>;
 		#size-cells = <0>;
diff --git a/arch/sandbox/dts/sandbox.dtsi b/arch/sandbox/dts/sandbox.dtsi
index 826db26fc2b..29306ac04da 100644
--- a/arch/sandbox/dts/sandbox.dtsi
+++ b/arch/sandbox/dts/sandbox.dtsi
@@ -19,6 +19,11 @@
 		#sound-dai-cells = <1>;
 	};
 
+	bootstd {
+		compatible = "u-boot,boot-std";
+		filename-prefixes = "./";
+	};
+
 	buttons {
 		compatible = "gpio-keys";
 
diff --git a/fs/Kconfig b/fs/Kconfig
index cda9f66cc93..aa13d4faa77 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -16,6 +16,8 @@ source "fs/fat/Kconfig"
 
 source "fs/jffs2/Kconfig"
 
+source "fs/sandbox/Kconfig"
+
 source "fs/ubifs/Kconfig"
 
 source "fs/cramfs/Kconfig"
diff --git a/fs/sandbox/Kconfig b/fs/sandbox/Kconfig
new file mode 100644
index 00000000000..b2af8482428
--- /dev/null
+++ b/fs/sandbox/Kconfig
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
diff --git a/fs/sandbox/Makefile b/fs/sandbox/Makefile
index 06090519bf4..880d59dd693 100644
--- a/fs/sandbox/Makefile
+++ b/fs/sandbox/Makefile
@@ -9,3 +9,4 @@
 # Pavel Bartusek, Sysgo Real-Time Solutions AG, pba@sysgo.de
 
 obj-y := sandboxfs.o
+obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += host_bootdev.o
diff --git a/fs/sandbox/host_bootdev.c b/fs/sandbox/host_bootdev.c
new file mode 100644
index 00000000000..0d12ee4ef74
--- /dev/null
+++ b/fs/sandbox/host_bootdev.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootdevice for MMC
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <bootdev.h>
+#include <bootflow.h>
+#include <bootmeth.h>
+#include <dm.h>
+#include <fs.h>
+
+static int host_get_bootflow(struct udevice *dev, struct bootflow_iter *iter,
+			     struct bootflow *bflow)
+{
+	int ret;
+
+	if (iter->part)
+		return log_msg_ret("max", -ESHUTDOWN);
+
+	bflow->name = strdup(dev->name);
+	if (!bflow->name)
+		return log_msg_ret("name", -ENOMEM);
+
+	ret = bootmeth_check(bflow->method, iter);
+	if (ret)
+		return log_msg_ret("check", ret);
+
+	bflow->state = BOOTFLOWST_MEDIA;
+	bflow->fs_type = FS_TYPE_SANDBOX;
+
+	ret = bootmeth_read_bootflow(bflow->method, bflow);
+	if (ret)
+		return log_msg_ret("method", ret);
+
+	return 0;
+}
+
+struct bootdev_ops host_bootdev_ops = {
+	.get_bootflow	= host_get_bootflow,
+};
+
+static const struct udevice_id host_bootdev_ids[] = {
+	{ .compatible = "sandbox,bootdev-host" },
+	{ }
+};
+
+U_BOOT_DRIVER(host_bootdev) = {
+	.name		= "host_bootdev",
+	.id		= UCLASS_BOOTDEV,
+	.ops		= &host_bootdev_ops,
+	.of_match	= host_bootdev_ids,
+};